20-7-2024 HUSAVIK, ICELAND - NOOTKA LUPINE (Lupinus nootkatensis)

In Iceland, the Nootka lupine has been designated an invasive species. The plant was introduced in the first half of the 20th century to combat erosion, speed up land reclamation and help with reforestation. Dense lupine cover and soil fertility can be gained within a relatively short time span, where the growth of the lupine is not limited by droughts. The plant has spread from the loose, eroded soil in which it was originally planted and is now found throughout the lowlands of Iceland.

The lupine is well suited for reclamation of large, barren areas because of its nitrogen fixation and rapid growth. Furthermore, it has an ability to extract phosphorus from compounds in poor soils. In spite of these good qualities, it has a tendency to become dominant and to colonize already vegetated areas such as dwarf shrub-highlands, where it overtakes the natural flora and threatens biodiversity. The growth of the Nootka lupine has led to public debate about its presence in Iceland, with some praising its improvement of soil through nitrogen fixation and the vibrant colour it brings to Iceland's landscape, and others concerned that it will eradicate native flora, particularly the favoured native crowberry and blueberry patches.

The initial expectation was for the Nootka lupine to retreat gradually along with increased fertility of the soil and give way for other species. This is evident on sites in Iceland where the lupine was introduced early, such as in Heiðmörk near Reykjavík. However, plant succession is towards a forb-rich grassland, often dominated by the invasive species Anthriscus sylvestris, meaning that careful management of lupine is necessary to prevent it from colonizing areas where its presence is not desirable.